Kick-starter mechanism for snowmobiles and the like

ABSTRACT

For snowmobiles and other vehicles equipped with rope-started internal combustion engines, a compact kick-starter mechanism provides convenient starting without dismounting from the vehicle. A slender housing is of sufficient diameter to house a single-turn winding drum whose perimeter is substantially the length to be pulled. Closely alongside the winding drum is a planetary gear system which effects this pull on a single kick of the external starter lever.

United States Patent 1191 Christensen et al.

[ Dec. 31, 1974 KICK-STARTER MECHANISM FOR SNOWMOBILES AND THE LIKE [76] Inventors: Frank G. Christensen, 62 Camwood Cres., Don Mills, Ontario; Rafael T.

Wulff, Dorset Post Office, Dorset, Ontario, both of Canada [22] Filed: Apr. 13, 1973 [21] Appl. No; 350,896

52 us. c1....123 185 B, 123/185 CA, 123/185 B, 74/89.19, 74/98 51 1111.01. F02h 3/04 [58] Field of-Search 123/185 R, 185 A, 185 B, 123/185 BA, 185 BB, 185 C,185 P, 185 cA,

[56] A References Cited UNITED STATES PATENTS 5/1912 Swern 123/185 CA 1,174,432 3/1916 Mohr 123/185 B A 1,335,345 3/1920 Mallard 123/185 B A 3,626,937 12/1971 Giovik 123/185 B X FOREIGN PATENTS QR APPLICATIONS 698,568 10/1940 Germany 123/185 S Primary Examiner-Charles J. Myhre Assistant Examiner-W. Rutledge, Jr.

[ 5 7 ABSTRACT For snowmobiles and other vehicles equipped with rope-started internal combustion engines, a Compact kick-starter mechanism provides convenient starting without dismounting from the vehicle. A slender housing is of sufficient diameter to house a single-turn winding drum whose perimeter is substantially the length to be pulled. Closely alongside the winding drum is a planetary gear system which effects this pull on a single kick of the external starter lever.

8 Claims, 3 Drawing Figures BACKGROUND OF THE INVENTION vehicles could be started in the manner of a motorcyle.

In conventional snowmobiles, however, the engine is not positioned favorably for employing a kick-starter such as used on motorcycles; nor are the engines used on snowmobiles ordinarily adapted for this type of starting.

SUMMARY OF THE INVENTION A principal purpose of the present invention is to adapt snowmobiles and other small vehicles employing engines of the pull-rope type, to kick-starting some what similar'to the starting of motorcycles, without altering the engine type or position, or interfering with starting it by pulling the rope. Another purpose is to provide an auxiliary kick-starter mechanism housed in a slender housing suited for affixation in a convenient position on the snowmobile or other vehicle. Further purposes will be apparent from the remainder of this specification.

I accomplish these purposes in the manner hereinafter described. Summarizing generally, I provide a narrow winding drum, whose circumference-is substantially equal to the distance the winding rope is to be pulled for starting. This diameter is of course substantial and calls for a relatively large diameter housing. I utilize this relatively large diameter to provide an internal sector gear as part of a planetary gear system; hence the housing may-be relatively shallow, with a conventional kick-start lever projecting. This lever is attached to a central shaft on which the winding drum and a central gear secured to it are mounted for relative rotation. A planetary cage lever, secured to the shaft, swings a planetary gear along the inside of the internal sector gear; the planetary gear in turn causes the winding drum gear to rotate through substantially a full revolution as the kick-start lever is moved from top to bottom.

Such a housing may be readily affixed to the side of the vehicle, with its shaft horizontal and located at the specific position most convenient for the operator of the vehicle. Thus the operator may step on the kickstart lever with all his weight, pulling the rope with greater torque and greater speed than would be possible by hand.

BRIEF DESCRIPTION OF THE DRAWINGS In the accompanying drawings:

FIG. 1 is an elevational view of a preferred embodiment of the present invention with the forward housing member partly broken away. a

FIG. 2 is a view principally in section taken along line 22 of FIG. 1.

FIG. 3 is a schematic view of the installation of the present invention on a conventional snowmobile.

DESCRIPTION OF THE PREFERRED EMBODIMENT The preferred embodiment of the invention is fitted into a shallow compact housing generally designated 10 which is generally circular and has a horizontal axis a which when mounted on a snowmobile, extends laterally. The housing member by which it is mounted is a circular back plate 11 having along the axis a a central bushing 12. The outer edge portion 13 of the back plate 11 includes simple mounting provisions, such as the mounting bores 14 for bolts not shown. The outer edge portion 13 is preferably thicker than the remainder of the plate 11, as best seen in FIG. 2.

The other housing member is a forward shallow panlike member 15 having a substantially cylindrical flange 16 whose diameter is such as to fit against and mate with the back plate 11 immediately inward of its edge portion 13. A tangential inlet is provided into the housing by a slot 17 in the flange l6 and a mating substantially tangential groove 18 in the thickened portion of the edge 13. Through the slot 17 and groove 18 passes the pull rope b (or an extension thereof) from the engine of the showmobile as seen in FIG. 3.

Along the axis a, the forward member 15 has a bushing 20. In it and the bushing 12 of the back plate 11 is mounted .a horizontal lateral shaft 21 having an extended portion 22 outwardly of the pan-like member 15. On the extended portion 22 is bolted or otherwise secured the radially inner mounting end 23 of a conventional kick-start lever 24 having at its radially outer end a hinged pedal 25 which is shown extended outward in FIG. 2. As is conventional, the pedal may have a spring, not shown, which turns it forward when not in use. Preferably the lever 24 has, radially outward of the housing flange 16, an inward offset 26, so that the unit may be as compact as possible.

The engine recoil may be adequate of itself to restore the lever 24 to upright position, shown in solid lines in FIG. I, after it has been forced downwardly through an arc of not more than to the fulldown position shown in dashed lines in FIG. 1. In the preferred embodiment, we however, provide, about the portion of the shaft outwardly of the forward member 15 and inwardly of the kick-lever mounting end 23, a conventional torsion spring 27, whose ends are engaged between said forward housing end 15 and lever mounting end 23'. Y t

Referring to FIG. 2, there is provided immediately adjacent to the back plate 1 1 a winding drum 28 having a central bore 29 on which it is supported by the shaft 21 with freedom to rotate. The circumference of the winding drum is preferably substantially equal to the distance which the rope b must be pulled for starting. The end of the rope b fits intothe periphery of the drum which preferably has a slightly concave edge surface 30 and is there secured by suitable means such as a machine screw 31. The width of the concave edge 30 is preferably no greater than necessary for a single width of the rope b; thus its circumference is sufficient to accommodate the necessary length of the rope b for starting. This permits the drum 28. to be exceptionally narrow. Together with the slot 17 and groove 18, the

drum 28 occupies what is referred to as the third plane of mechanism within the housing 10.

In what is referred to as a middle or second plane of mechanism, is a winding drum gear 34 formed integral with or mounted securely onto the outer surface of the winding drum 28 and concentric therewith.

The pan-like member is preferably formed by casting to provide a circular step 35 within the intersection of its forward surface and the cylindrical flange 16. The step 35 serves as a mounting for an internal sector gear 37, to present it in the same middle plane of mechanism as the winding drum gear. The sector gear 37 occupies an angular length somewhat greater than 180.

The sector gear 37 is either secured by bolts to the step 35 or cast integrally with it. The sector 37 is available space within the housing 10. it location in the middle plane of mechanism brings it adjacent to the outer edge of the winding drum 28. However, as seen in the drawings, the radius of the winding drum 28 is even greater, so that with the rope b substantially the entire inner diameter of the cylindrical flange 16 is occup ied.

lntermeshed between the sector gear 37 and the winding drum gear 34 is a planetary gear 40 held in the middle plane of mechanism on a stub shaft 41 which projects inwardly from the laterally outer end of the planetary cage lever 42 which rotates in the plane of mechanism adjacent to the inner surface of the pan-like member 15, which plane is hereafter referred to as the first plane of mechanism. The radially inner end of the cage lever 42 is mounted securedly onto the central shaft 21 in such first plane of mechanism.

To provide a stop for the angular rotation of the cage lever 42, so that the kick-start lever 24 will have the desired length of angular movement, a stop block 44 is secured in said plane first adjacent to the inner surface of the pan-like member 15. It is mounted to the member 15 in any convenient manner, as by countersunk screws 45, or may be cast integral therewith.

On assembly of the parts as shown in FIG. 2, the aft edge of the cylindrical flange 16 of the pan-like member 15 is secured to the back plate 11, which is bored to receive countersunk screws 45.

Referring to FIG. 3, the assemblied starter is mounted at some convenient location along the vertical side surface of the snowmobile a near the drivers seat and low enough for the driver to engage the pedal 25 with his foot. The mounting bores 14 are used to bolt the starter in place, with the pull rope b extending forwardly through the tangential slot end groove l7, 18. The rope b in turn is lead through eye bolts e located conveniently along the side of the snowmobile d; these serve as guides through which the rope may be pulled.

In use, the snowmobile operator places his weight on the pedal 25, driving it down from the solid line position of FIG. 1 to the phantom line position, which may be substantially 180. Within the housing 10 the cage lever 42 is driven through a corresponding angle along the internal sector gear 37, and its rotation causes the winding drum gear 34 to rotate approximately a full turn, drawing the pull rope b substantially a full turn around the winding drum 28. The downward kick motion is limited by the contact of the side surface of the cage lever 42 with the stop block 44. When the operator releases his weight from the pedal 25, it is driven back upward by the torsion spring 27, as well as by the recoil force exerted through the rope b.

The present invention permits an operator to pull the rope b with much greater force and suddenness than if it were pulled by hand. It also permits him to start the snowmobile without dismounting therefrom, and overcomes the inconvenience of starting, by hand, an engine occupying the conventional forward place in the snowmobile.

The high starting torque afforded by the present invention is achieved by a minimum of size and weight. Thus, in a typical installation, the present starter mechanism may weigh only 6 or 7 pounds, in contrast to over 40 pounds required for all the components of an electrical starting system. Most significantly, the entire mechanism occupies very little space; thus, the housing may be only one and /2 to 2 inches thick and 6 to 7 inches in outer diameter. The excellent starting torque and overall small size follow from the utilization of the maximum interior diameter of the housing for the winding drum an internal sector gear, with the entire mechanism occupying the three adjacent planes as described.

Accordingly, the present starter is of particular value for any type of small vehicle employing a rope-started internal combustion engine, or in connection with any other use of such an engine wherein kick-starting is desirable.

We claim:

1. For starting an internal combustion engine of the type startable by pulling on a rope or other windable member,

a kick-starter mechanism comprising a winding drum onto which such windable member may be engaged and wound, the winding drum mounting a concentric, outward-toothed gear,

a housing formed about a central axis having inward of its outer periphery an internal sector gear whose pitch radius, measured from said axis, is spacedly outward of the pitch radius of said'winding drum gear, and

central shaft means supported in said housing for angular rotation on said housing axis, on which shaft means said winding drum and its gear are supported for rotation within said housing,

said shaft means having secured thereto a kick-start lever external of the housing and a planetary cagelever within said housing, together with a planetary gear mounted on said cage lever for rotation intermeshed between said internal sector gear and said winding drum gear,

whereby angular movement of the kick-start lever from upward position to downward position rotates the winding drum.

2. A kick-starter mechanism as defined in claim 1,

wherein the housing axis is horizontal and lateral, and

the pitch diameter of the winding drum gear is substantially half that of the internal sector gear,

whereby to afford substantially a full turn of the winding drum for angular movement of the kick-start lever.

3. A kick-starter mechanism as defined in claim 1, lever to upward position.

wherein 6. A kick-start mechanism as defined in claim 1,

the housing has a tangential inlet for such windable characterized in that member and I the aforesaid mechanism within said housing is e i g drum has a circumference Substantially 5 mo'unted therein substantially along three adjacent equal to the distance such windable member is to be pulled for starting and has a winding width sufficient for only one width of such windable member,

planes, namely a first plane including said cage lever secured on said shaft and mounting at its outer end the base of a stub shaft projecting to where-by to occupy a narrow Space within the housing 10 a second, middle plane, including said planetary gear alongside the space occupied by the internal sector gear, planetary gear and winding drum gear, thus minimizing the required housing width.

4. A kick-starter mechanism as defined in claim 1,

ternal sector gear and said outward-toothed gear, and

wherein a third plane including said winding drum.

the housing comprises 7. A kick-start mechanism as defined in claim 6, the a circular housing back plate having mounting provifirst plane further havms sions at its Outer margin, and stop means secured to the inner surface of the pana hollow panqike fmward housing member having a like member to establish extreme positions for said flange mating with the back plate inwardly of said cage levermargin, d h i 8. A kick-start mechanism as defined in claim 6, the internal sector gear is presented along the inner the Outel: g of Said Wmdmg drum bemg adlacent surface of the flange of said forward housing memt0 the Internal Sector g ber. 7 whereby to afford maximum winding drum diameter 5. A kick-starter mechanism as defined in claim 1, with minimum housing therebeneath. together with spring means to restore the kick-start mounted on said stub shaft, also including said in- 

1. For starting an internal combustion engine of the type startable by pulling on a rope or other windable member, a kick-starter mechanism comprising a winding drum onto which such windable member may be engaged and wound, the winding drum mounting a concentric, outwardtoothed gear, a housing formed about a central axis having inward of its outer periphery an internal sector gear whose pitch radius, measured from said axis, is spacedly outward of the pitch radius of said winding drum gear, and central shaft means supported in said housing for angular rotation on said housing axis, on which shaft means said winding drum and its gear are supported for rotation within said housing, said shaft means having secured thereto a kick-start lever external of the housing and a planetary cage lever within said housing, together with a planetary gear mounted on said cage lever for rotation intermeshed between said internal sector gear and said winding drum gear, whereby angular movement of the kick-start lever from upward position to downward position rotates the winding drum.
 2. A kick-starter mechanism as defined in claim 1, wherein the housing axis is horizontal and lateral, and the pitch diameter of the winding drum gear is substantially half that of the internal sector gear, whereby to afford substantially a full turn of the winding drum for 180* angular movement of the kick-start lever.
 3. A kick-starter mechanism as defined in claim 1, wherein the housing has a tangential inlet for such windable member, and the winding drum has a circumference substantially equal to the distance such windable member is to be pulled for starting and has a winding width sufficient for only one width of such windable member, whereby to occupy a narrow space within the housing alongside the space occupied by the internal sector gear, planetary gear and winding drum gear, thus minimizing the required housing width.
 4. A kick-starter mechanism as defined in claim 1, wherein the housing comprises a circular housing back plate having mounting provisions at its outer margin, and a hollow pan-like forward housing member having a flange mating with the back plate inwardly of said margin, and wherein the internal sector gear is presented along the inner surface of the flange of said forward housing member.
 5. A kick-starter mechanism as defined in claim 1, together with spring means to restore the kick-start lever to upward position.
 6. A kick-start mechanism as defined in claim 1, characterized in that the aforesaid mechanism within said housing is mounted therein substantially along three adjacent planes, namely a first plane including said cage lever secured on said shaft and mounting at its outer end the base of a stub shaft projecting to a second, middle plane, including said planetary gear mounted on said stub shaft, also including said internal sector gear and said outward-toothed gear, and a third plane including said winding drum.
 7. A kick-start mechanism as defined in claim 6, the said first plane further having stop means secured to the inner surface of the pan-like member to establish extreme positions for said cage lever.
 8. A kick-start mechanism as defined in claim 6, the outer edge of said winding drum being adjacent to the internal sector gear, whereby to afford maximum winding drum diameter with minimum housing therebeneath. 